6 to 24 inches
Grows in shallow, brackish and salty waters and is especially common in nutrient-rich areas. Can be free-floating in the water or attached to rocks, pilings and other hard surfaces. Often found washed up on the shore.
Found throughout most of the Chesapeake Bay, except in the extreme upper Bay.
Sea lettuce grows in thin, green sheets with wavy, ruffled edges. It looks similar to wilted lettuce. It grows to be 6 to 24 inches and usually grows in large masses.
Reproduction and Life Cycle
Sea lettuce goes through two reproductive phases. During the first phase, adults produce spores by meiosis. The spores settle and grow to form male and female plants. During the second phase, the male and female plants produce gametes by mitosis. The gametes unite and develop into adult plants. When sea lettuce dies, it sinks to the Bay’s bottom, where it is decomposed by bacteria. During this process, bacteria consume oxygen until there is little or none left in these bottom waters.
Did You Know?
- Sea lettuce is commonly referred to as seaweed.
- When abundant, sea lettuce can smother bay grasses growing in the shallows.
- Large masses of sea lettuce are often an indicator of nutrient pollution in the water.
- In some parts of the world, people eat sea lettuce in soups and salads.
Sources and Additional Information
- Underwater Grasses in Chesapeake Bay & Mid-Atlantic Coastal Waters by Maryland Sea Grant
- Chesapeake Bay: Nature of the Estuary, A Field Guide by Christopher P. White
- Sea Lettuce (Ulva lactuca) – University of Rhode Island